1. Field of Invention
The present invention relates generally to the field of vibratory devices operable as a two-mass vibrating systems moving bulk material in a linear direction as a feeder, conveyor, packer, scavenger, screen, grizzley or foundry shakeout. The method and apparatus of the present invention has particular application to a new method of attaching resilient members between the two-masses of such a vibrating device, to thereby increase the spring rate (lbs/in.) within a defined mounting space.
Two devices incorporating the present invention are briefly described in the present disclosure. Full and complete descriptions of the devices themselves are located within commonly invented U.S. Pat. Nos. 4,218,929 and 5,547,068, hereby incorporated by reference.
2. Discussion of Prior Art
Two-mass vibratory work conveyors, known in the art, incorporate a number of different types of resilient members in order to control the transference of energy between the two masses. One popular type of resilient member which provides exemplary performance is cylindrical elastomer springs. The problem of degraded performance of the elastomer due to increased temperatures within the springs, however, has not been adequately addressed as indicated in the following discussion of related prior art.
The patent to Spurlin (U.S. Pat. No. 4,218,929), the present inventor, provides for a vibratory feeder which supports a trough mass above an exciter mass on rectangular elastomer springs rather than cylindrical elastomer springs. In addition, the spring's inner support is connected to the trough at a single point, while the outer support is connected to the exciter mass in two places.
The patent to Dean et al. (U.S. Pat. No. 4,272,366) provides for a Heavy Duty Two Mass Vibratory Machine. The vibratory apparatus of this device connects the two masses using a plurality of resilient members. The resilient members described, however, are not cylindrical elastomeric springs and therefore no teaching of heat-sinking an inner or outer tubular member is provided.
The patents to Hallman et al. (U.S. Pat. No. 4,754,870) and Yun et al. (U.S. Pat. No. 4,795,552) provide for two mass vibrating devices with resilient member mounting configurations representative of the prior art. The resilient means connecting the two masses are connected at both ends to the masses; however the resilient means are coil springs rather than cylindrical elastomer springs and the springs have one end attached to one mass and the other end attached to the other mass.
The patent Grunau et al. (U.S. Pat. No. 5,366,210) provides for a vibration absorber which maintains the elastomer's performance even during periods of heat buildup. A second spring assists the primary spring when the primary spring is degraded due to its temperature. No discussion of heat-sinking is provided, however.
The patent to Spurlin (U.S. Pat. No. 5,547,068), the present inventor, provides for a two-mass vibratory device functionally connected, using the prior art method, with cylindrical elastomer springs.
The patent to Colford (U.S. Pat. No. 5,695,176) provides for a vibration damper which uses a heat activated coating which swells in order to maintain pressure on an elastomeric spring whose performance is degraded due to increasing temperature.
The patent to Seki et al. (U.S. Pat. No. 5,884,893) provides for a cylindrical elastomer vibration isolator which assists in heat dissipation from an attached motor. However, in direct contradiction of the present invention, the elastomer is actually part of the heat sink and used to transport heat from the motor to a large surface area rather than the elastomer being the heat source.
Whatever the precise merits, features and advantages of the above cited references, none of them achieve or fulfill the purposes of the present invention. In particular, the prior art does not provide for a method of increasing the spring rate per mounting area by an improved method of dissipating heat from the elastomer and shaft within cylindrical elastomer springs which connect two masses in a two-mass vibratory device.